5,021 articles
Gaining stream
A gaining stream is a stream reach that receives groundwater, which discharges through the streambed where the water table stands higher than the stream's water surface, sustaining baseflow.
Gale warning
A gale warning is a marine weather warning issued for sustained winds, or frequent gusts, of 34 to 47 knots over water, excluding winds from tropical cyclones.
Galena
Galena, also known as lead glance or blue lead, is lead sulfide, the world's most important ore of lead, used by humans for thousands of years.
Gall–Peters projection
The Gall–Peters projection, also known as the Peters projection, is a cylindrical equal-area map projection that preserves area exactly while distorting shapes, presented by James Gall in 1855.
Gamchen
Gamchen (Вулкан Гамчен, Sopka Khamchenskaya) is a complex of four stratovolcanoes in Kamchatka's Eastern Volcanic Arc, 2,539 m high, last erupting 188 BCE (VEI 3), with fumaroles and a UNESCO setting.
Gamma-ray logging
Gamma-ray logging is a borehole geophysical method measuring gamma radiation in and around a drill hole, developed in the 1930s for uranium exploration and now among the most widely used well logs.
Gammarus
Gammarus is a genus of amphipod crustaceans, mostly freshwater and brackish-water scavengers that shred leaf litter in streams, widely used as sentinel organisms in aquatic ecotoxicology.
Garlock Fault
The Garlock Fault is a major east–west, left-lateral strike-slip fault in southern California, running about 250 km from the San Andreas Fault to Death Valley and capable of magnitude 7.6 earthquakes.
Garnet
Garnet is a group of silicate minerals that supplies gemstones in nearly every color and a hard abrasive for waterjet cutting; it is January's birthstone.
Gateway belief model
The gateway belief model (GBM) is a dual-process theory of attitude change, proposed in 2015, in which perceived scientific consensus shapes climate beliefs and support for public action.
GCAM (integrated assessment model)
GCAM (the Global Change Analysis Model) is an open-source integrated assessment model linking energy, water, agriculture and land use, the economy, and climate, developed at the Joint Global Change Research Institute.
Gede-Pangrango
Gede-Pangrango: twin stratovolcanoes (Gede 2,958 m, Pangrango 3,019 m) 60 km south of Jakarta, West Java, last erupting in 1957; their rain forest forms Gunung Gede Pangrango National Park, a major hiking and biodiversity destination.
Gelasian
The Gelasian is a geological stage from about 2.58 to 1.80 million years ago, now the lowest stage of the Pleistocene and defining the base of the Quaternary.
Gelisol
Gelisol is one of the twelve soil orders in USDA Soil Taxonomy, defined by permafrost within 100 cm of the surface; in the United States, Gelisols occur only in Alaska.
Gemstone
A gemstone, also called a precious or semiprecious stone, is a mineral or organic material cut and polished for jewelry and valued for beauty, durability, and rarity.
Geo-KOMPSAT-2A
Geo-KOMPSAT-2A, also called Cheollian 2A, is a South Korean geostationary weather satellite launched in December 2018 from French Guiana, operated by the Korea Meteorological Administration.
Geochemical baseline mapping
Geochemical baseline mapping is the systematic sampling and analysis of soils, stream sediments, and waters to establish element concentrations across a region, against which contamination or change is measured.
Geochemical exploration
Geochemical exploration is the systematic measurement of chemical properties in natural materials such as rock, soil, sediment, and water to locate mineral deposits through their dispersion halos.
Geochemistry
Geochemistry is the branch of earth sciences studying the chemistry of the Earth, its elements' distribution, and the processes that shaped the planet, founded by Victor Moritz Goldschmidt.
Geochimica et Cosmochimica Acta
Geochimica et Cosmochimica Acta, also known as GCA, is a peer-reviewed scientific journal covering geochemistry and cosmochemistry, published by Elsevier since 1950 and jointly sponsored by the Geochemical Society and the Meteoritical Society.
Geode
A geode is a roughly spherical rock with a hollow interior cavity lined with mineral crystals, formed when dissolved minerals precipitate in volcanic or sedimentary rock.
Geodesy
Geodesy, also called Erdmessung or Geodetic Science, is the science of measuring the Earth's shape, orientation in space, and gravity field, and how they change.
Geoengineering Model Intercomparison Project (GeoMIP)
The Geoengineering Model Intercomparison Project (GeoMIP) is an international project, started in 2010, that runs standardized climate model experiments to study solar geoengineering's effects and impacts.
Geographical zone
A geographical zone, also called a geographical climate zone, is one of the principal zones into which the Earth is divided by climate, roughly demarcated by latitude and altitude.
Geoid
The geoid is the equipotential surface of Earth's gravity field that best fits global mean sea level; it is irregular, undulating above and below a reference ellipsoid.
Geologic hazard
A geologic hazard is a natural hazard of geological origin, such as an earthquake, landslide, volcano, or sinkhole, that can cause loss of life or property damage.
Geologic map
A geologic map is a map showing the distribution of rock and sediment units at the Earth's surface, with colors and symbols marking units of different age, composition, and origin.
Geologic modeling
Geologic modeling is the construction of digital 3D representations of the Earth's subsurface using explicit or implicit methods, allowing estimation of properties like permeability at any point.
Geologic temperature record
The geologic temperature record reconstructs past surface and water temperatures from physical, chemical, and biological proxies in rocks, sediments, and ice, reaching back millions of years before thermometers.
Geologic time scale
The geologic time scale divides Earth's roughly 4.6-billion-year history into eons, eras, periods, epochs, and ages, with boundaries set by the International Commission on Stratigraphy and dated radiometrically.